Pump



P. SPENCE PUMP Filed Sept. 13, 1957 Jan. 10, 1961 INVENTOR P/PUASENpE/vce ATTORN Y3 IHJKE' Aw y/ll W \\\\\\\\\\\\i&

United States Patent PUMP 'Paulsen Spence, P.0. Box 77, Baton Rouge, La.

Filed Sept. 13, 1957, Ser. No. 683,790

1 Claim. (Cl. 103-103) My invention relates to a pump or the like.

In centrifugal pumps and like machines, the impeller is usually or veryoften threaded onto the drive shaft, which extends into the pump casing.The drive shaft usually has a substantial shoulder thereon, and theimpeller is screwed on the shaft and abuts very securely against theshoulder on the shaft. Since both the impeller and the shaft are usuallyformed of ferrous metal, the impeller and shaft often corrode and tendto stick very tightly to each other so that it is virtually impossibleto unscrew the impeller from the shaft when it becomes necessary to takethe pump apart.

It is an object of the invention, therefore, to provide means forinhibiting the corrosion of a pump impeller or the like to a shaft.

It is another object to provide means for providing a joint between apump impeller and a shaft, which may be readily broken, and which willnot be subject to corro- Briefly stated, in a preferred form of theinvention as applied to a centrifugal pump, the drive shaft extends intothe pump casing and the impeller is threaded or otherwise wedginglysecured to the drive shaft so as to be driven thereby during normaloperation. The impeller or the like is usually threaded to the shaft,and the latter has a shoulder for cooperation with an abutment surfaceor shoulder on the impeller so as to limit the position of the impelleron the shaft. Instead of having the shoulder and the impeller in directengagement where they might corrode so as to render removal of theimpeller from the shaft impossible or very diflicult, I interpose awasher between the shaft and the impeller so as to render it fairly easyto break the connection between the shaft and the impeller and removethe latter from the shaft when it becomes necessary to dismantle thepump for any reason.

In the preferred form, the washer or liner between the shaft and theimpeller consists of a washer of stainless steel, which is hardened andground to a smooth surface. Thus, when the impeller is tightly screwedonto a shaft, the impeller and shaft bind tightly on the stainless steelwasher so that the pump operates normally. However, when it is necessaryto remove the impeller from the shaft, reasonable force in the rightdirection will break the frictional hold between the impeller and theshaft, and due to the fact that the washer is stainless steel andseparates the shaft and impeller, there is no chance of having theimpeller or the shaft corrode into tight engagement with either thestainless steel washer or with each other.

In the drawings which show, for illustrative purposes only, a preferredform of the invention Fig. 1 is a view in side elevation of acentrifugal pump, parts being broken away on a central vertical planeand shown in section to illustrate interior construction;

Fig. 2 is an enlarged fragmentary sectional view, illustrating theinvention as applied to a part of the pump of Fig. 1.

r 2,967,486 Patented .lamlO, 1961 2 The invention is not limited to acentrifugal pumpfsinlce the principles of the invention are of broaderapplication and may be employed in various connections, but a pumpapplication is typical and is herein described.

The centrifugal pump comprises the usual casing 5,

having a rotatable impeller 6 therein. The drive shaft 7 extends througha stuffing-box 8 and suitable bearing into the casing, where it issecured to the shaft. In the form illustrated, the shaft 7 has asubstantial shoulder 9 formed thereon for abutment by a part of theimpeller. V The end of the shaft is threaded as indicated at 10. Theimpeller, or rather a part carried by the impeller, such as the plug nut11, is internally threaded so as to engage the threads 10 for holdingthe impeller in place. In the form illustrated, the plug nut 11 fits ina bore or recess 12 in the impeller and may be secured to the impelleras by welding, as shown at 13. The bottom of the plug nut 11 fits theshoulder at the bottom of the recess 12 so that, in effect, the plug nutbecomes an integral part of the impeller. A part of the impeller has anabutment face or surface 14, complementary to the corresponding surfaceon the shoulder 9 of the shaft 7.

Normally, the impeller would abut directly against the shoulder 9, anddue to the fact that both the impeller and the shaft are usually formedof ferrous metal, they would be likely to corrode or rust to such anextent as to bind the two together so as to make it next to impossibleto break the impeller loose from the shaft when it is desired todismantle the pump for any reason.

My invention relates particularly to means for preventing such corrosionand permitting easy removal of the impeller from the shaft when desired.Between the impeller surface 14 and the corresponding abutment face onthe shoulder 9, I interpose a washer 15 of stainless steel, which ishardened and ground to a smooth finish, and which fits both of thesurfaces 14 and 9 with good fiat fits. Thus, when the shaft is screwedup tightly onto the impeller, both the shaft and the impeller bindtightly on the stainless steel washer 15 and cause the impeller andshaft to rotate as a unit as desired.

Now, since the washer 15 is of stainless steel, there is no chance ofcorrosion between the impeller or the shaft and the washer, or betweenthe impeller and shaft themselves. Thus, the joint will be at all timesvery secure yet frictional, and when it is desired to remove the shaftfrom the impeller, it will be only necessary to exert a reasonable forceso as to break the frictional contact between the washer 15 and therespective shaft and impeller surfaces. As has been heretofore stated,under normal conditions without the washers 15, impellers and shaftsoften become so corroded that it is well nigh impossible to unscrew theshafts from the impellers, and shafts or impellers may be broken orseriously marred.

While the invention has been described in considerable detail and apreferred form illustrated, it is to be understood that various changesmay be made within the scope of the invention as defined in the appendedclaim.

I claim:

A pump comprising a casing, an impeller made of ferrous metal in saidcasing, a drive shaft made of ferrous metal extending into said casing,said shaft being threaded and said impeller having a threaded connectionwith said shaft, said shaft having an abutment shoulder and saidimpeller having a cooperating abutment surface, a washer interposedbetween said shoulder and abutment surface, said washer being formed ofstainless steel which is hardened and ground to a smooth finish toprevent rusting 0 ofsaid impeller or shaft to said washer or to eachother.

(References on following page) 3 References Cited in the file of thispatent 2,892,503

UNITED STATES PATENTS 2,220,669 Allen 'Nov. 5, 1940 695,948 2,339,099Namur Jan. 11, 1944 851,726 2,811,339 Osborne ct a1 Oct. 29, 19571,108,299

4 Hood et a1 June 30,1959

FOREIGN PATENTS Great Britain Aug. 19, 1953 Germany Oct. 6, 1952 FranceOct. 24, 1955

